Systems development processes have received significant negative publicity due to failed projects, often at large costs, and performance issues that continue to plague IS managers. This study complements existing systems development research by proposing a knowledge management perspective for managing tacit and explicit knowledge in the systems development process. Specifically, it proposes that collaborative exchange and integration of explicit knowledge across phases of the development process positively influence the performance of systems development. It also suggests that process formalization not only directly impacts development performance but also moderates the performance effects of the knowledge integration factors. Data for the empirical study were collected from 60 organizations that are part of a user group for one of the world’s largest software development tool vendors.